Overview
Vector-borne diseases are illnesses caused by the bite of disease-causing pathogens like mosquitoes, houseflies, ticks etc. There are various vector-borne diseases, including Malaria, Dengue, Yellow Fever, Plague, Zika Virus, etc.
This blog discusses the types, causes, symptoms and treatment of different vector-borne diseases.
Vector-borne diseases are illnesses caused by parasites, viruses and bacteria transmitted by vectors. Vectors are living organisms that transmit infectious pathogens between humans or from animals to humans.
These vectors are bloodsucking insects that ingest disease-producing parasites from an infected host during a blood meal and then transmit them to a new host.
After becoming infectious, vectors can transmit infections for the rest of their life during each bite.
According to WHO, about 700,000 deaths occur due to vector-borne diseases like Malaria, yellow fever, dengue, chikungunya, onchocerciasis, leishmaniasis etc.
Arthropod species like mosquitoes, ticks, bugs, sandflies and blackflies usually transmit vector-borne diseases.
The spread of disease usually depends on the environment, population density, urbanisation etc. People living near water bodies, dense grass growth regions, etc., may experience vector-borne disease outbreaks.
However, many of these vector-borne diseases are preventable through proper protective measures.
Types of vectors that spread vector-borne disease
| Vector- Borne Disease | Type of pathogen | Vectors |
| Chikungunya, Dengue, Yellow Fever, Zika | Virus | Aedes Mosquito |
| Malaria | Parasite | Female Anopheles mosquito |
| Japanese encephalitis and West Nile fever | Virus | Culex mosquito |
| American trypanosomiasis | Parasite | Triatomine bugs |
| African trypanosomiasis (Sleeping sickness) | Parasite | Tsetse flies |
| Leishmaniasis | Parasite | Sandflies |
| Typhus | Bacteria | Lice |
| Plague | Bacteria | Fleas (transmitted from rats to humans) |
| Crimean-Congo hemorrhagic fever | Virus | Ticks |
| Lyme disease | Bacteria | Ticks |
How severe is vector-borne disease?
Vector-borne diseases are among the most severe and unpredictable conditions. The prevention and control of these diseases are extremely challenging since the organisms are inherent to the environment where they are spreading.
Vector-borne diseases pose a greater threat than diseases transmitted through human contact due to their ability to spread faster and on a larger scale. They transmit diseases from different animals, including mice, rats, monkeys, birds, dogs, etc., to humans and open the door to spreading microorganisms that cause severe illnesses. Treating such diseases is difficult, and the vector must be eliminated to prevent the spread of diseases.
Causes of Vector-borne disease
Vector-borne diseases are caused by the bite of infected vectors like mosquitoes, ticks, black flies, snails or sandflies, which are the primary carriers of the disease. These vectors suck human blood; it ingests the disease-causing pathogen from an infected animal or human and then transmit it to other humans.
Possible places of presence of disease-causing vectors
- Swimming pools and ponds with stagnant water
- Places where rainwater stagnates, like parks
- Equipment and places that have been abandoned
- Toilets or kitchens with open water tanks
- Water stagnant in flower pots
- Burrows of rodents and dark places
- Buildings with stagnant water on their roofs
- A swimming pool, pond or swamp, especially in an agricultural area
- Animal husbandry and agricultural sheds
- Beds and unhygienic sleeping areas
Types of disease caused by mosquitoes, flies and snails include
| Causative Organisms | Vector-Borne Disease |
| Mosquito-borne diseases | Malaria, Dengue fever, Yellow fever, Chikungunya, Elephantiasis |
| Flies | Dysentery, Diarrhoea, Typhoid, Cholera, Shigellosis, Certain helminth infections, Eye infections – trachoma and epidemic conjunctivitis |
| Ticks | Lyme disease, Tick-borne meningo encephalitis, Crimean–Congo hemorrhagic fever, Tick-borne relapsing fever, Qfever, Tick-borne spotted fevers, Babesiosis, Ehrlichiosis Tularemia |
| Snails | Angiostrongyliasis, Clonorchiasis, Fascioliasis, Paragonimiasis, Schistosomiasis |
Symptoms of Vector-borne disease
The symptoms of vector-borne diseases vary depending on the conditions and the disease-causing pathogens. Some common symptoms include
| Disease | Symptoms |
| Chikungunya | Fever, Joint pain, Muscle ache, Headaches, Nausea, Fatigue, Skin rashes, Joint Pain may last for weeks |
| Dengue | Sudden high fever, Severe headache, Muscle pain, Joint pain, Nausea, Vomiting, Swollen lymph, Skin rashes |
| Yellow Fever | Fever, Muscle pain, Chills, Headaches, Loss of appetite, Nausea, Abdominal pain, In severe cases symptoms include gastric bleeding, dark coloured urine, vomiting |
| Zika Virus | Moderate fever, Conjunctivitis, Headache, Joint stiffness, muscle pain, Eye Pain |
| Malaria | Fever, Chills, Sweating, Headache, Nausea, Body aches, Diarrhea, Vomiting, Breathing issues, Chest pain, In severe cases malaria leads to Jaundice. |
| Japanese encephalitis | Fever, headache, Vomiting, Neurological symptoms, About 20 to 30 per cent of people die who reports brain infection |
| West Nile Fever | Fever, Headache, Fatigue, Body aches, Nausea, Skin rashes |
| Plague | Pneumonia, Shortness of breath, Chest pain, Cough, Bubonic Plague fills sores with pus |
| Typhus | High fever, Headache, Chills, Coughing, Severe muscle pain Fatigue |
Treatment of Vector-Borne disease
Viral vector-borne diseases can’t be treated. Parasitic infections like Malaria and Dengue can be treated using drugs like quinone, which prevents pathogen growth. Doxycycline and chloramphenicol are used to treat bacterial infections.
Here are some preventive measures to protect you from vector-borne disease
- One can take vaccines to prevent vector-borne diseases like yellow fever, encephalitis and more.
- Take necessary precautions before you travel to vector-borne disease outbreak locations.
- Always maintain hygiene, and make sure there’s no stagnant water near your place.
- Cover your body from head to toe before going outside.
- Apply insect/mosquito repellents on unprotected skin.
- Avoid contact with infected people or animal
- Check the vessels before cooking and food storage. Maintain healthy hygiene.
- Get vaccinated against all the diseases.
Summary
A major aspect of vector-borne diseases is behavioural change. Educating the people and improving awareness becomes necessary for people to protect themselves and their communities from mosquitoes, ticks, bugs, flies and other such vectors and diseases.
FAQs
What are Mosquito-Borne Diseases?
When a mosquito carrying disease-causing pathogens bites a person, it transmits it into the human body. A person can prevent a disease from spreading by preventing mosquitoes, isolating infected individuals from healthy ones, or giving vaccines to healthy individuals when the risk of infection is higher.
List of main mosquito-borne diseases
1· Malaria
2· Dengue fever
3· Yellow fever
4· Chikungunya disease
5· Elephantiasis
Is Dengue a vector-borne disease?
What are the most common vectors of human diseases?
1· Mosquito
2· Flies
3· Ticks
4· Snails.
